Method for improving efficiency of spiral swing oil cylinder
Improving the overall efficiency of the spiral swing oil cylinder is mainly to improve the transmission efficiency of the spiral pair and the efficiency of the internal leakage volume. Improving the efficiency of the spiral pair transmission starts from the following two aspects:
1. Using ball screw pair, its efficiency can reach about 94% to 98%. The double-screw swing cylinder using the ball screw pair has become more and more widely used as a standard component due to its high efficiency, long life, flexible rotation, and reduced processing costs. The spiral output shaft can adopt a single arc structure with simple processing technology, the ball nut and the piston are connected by screws, and the transmission gap is adjusted by a washer.
The ball nut uses a ball inner circulation reverser. This ball nut has a small radial size, good rigidity and low friction loss. To solve the problem of low volumetric efficiency, the method of removing the spiral pair from the oil cavity can be adopted. Under the action of the straight spline pair, the piston only performs linear reciprocating motion in the cylinder. The spiral pair integrated with the piston is detached from the oil chamber of the cylinder. Therefore, when pressure oil is applied to port B, only a small amount of oil leaks to the spiral pair through the spline, which functions to lubricate the spiral pair. In this structure, the spline pair only plays a role of restricting the circumferential movement of the piston, so if in order to reduce the leakage amount of the spline, a single key can be used instead of the spline.
2. Reasonably select the material of the spiral pair. Spiral rods and spiral mothers are usually made of different materials to obtain a lower coefficient of friction. The spiral rod is generally made of medium carbon steel or alloy steel. For small and medium load screws in precision instruments, T8A, T10A or CrMn are generally used. The spiral mother is made of tin bronze or wear-resistant cast iron. When the accuracy is not high, wear-resistant cast iron or nylon is used; when the accuracy is high, tin bronze or cast brass is used; or a layer of bronze or Bearing alloys, etc.